Graphene shows stable characteristics and high electric mobility, and has accumulated considerable interest as a material for use in next generation semiconductor devices. However, in order to show semiconductor characteristics, the graphene is typically required to be formed as a channel having a nanoscale line width, since the graphene basically has a metallic characteristic.
For example, it is currently understood that the graphene is required to have a line width of 1-2 nm in order to have a silicon band gap, i.e., about 1.11 eV. However, it is not possible to cut the graphene to such a narrow nanoscale line width (less than 3 nm) by presently available semiconductor processing techniques. Accordingly, graphene semiconductor devices are not yet practically realized although there has been considerable interest in using graphene.